1. Field of the Invention
The present invention relates to an apparatus and method for displaying the unbalance of rotors during measurement thereof, the rotors being clamped on a motor-driven shaft.
2. Description of the Prior Art
Apparatuses and techniques for balancing unbalanced rotors have been known in various forms. Typical of such prior art apparatuses and techniques are those disclosed in German Pat. Nos. DE-AS 2732738 and DE-AS 2701876.
The latter relate to equipment for balancing rotors, epsecially automobiles, in two correction planes, wherein the rotor is mounted on a clamping shaft, with the clamping shaft being supported directly on the machine housing, or in an intermediate housing and via transducers. Furthermore, the known apparatuses and techniques involve the employment of unbalance measuring devices to determine and read out the amount and location of unbalance.
To calibrate balancing machines of the prior art, a perfect balanced rotor had to be clamped on the shaft, and artificial unbalance created by insertion of an unbalanced mass of known weight. The weight and location of this unbalanced mass were then measured, during rotation of the rotor, by means of an unbalance measuring device, and the meters of the balancing machine were then adjusted accordingly.
Such prior art techniques have been burdened by serious disadvantages. For example, once the meters of the balancing machine were adjusted, the purpose being to insure conversion of the unbalance forces into electrical signals independent of temperature and time, such adjustments could be retained for a long period of time only at considerable expenditure, and only by the use of sophisticated and expensive components. On the other hand, constant accuracy over a long period is especially required of the transducers and the complete electronic measuring unit. Thus, perfect balance in such prior art apparatuses and methods could only be assured if the above-described time-consuming and complicated calibration processes were repeated relatively frequently.